There is known an electrophotographic image forming apparatus such as a laser printer or an LED printer. Such an image forming apparatus uses a developing cartridge. The developing cartridge includes a developing roller for supplying toner. The developing cartridge known in the prior art is inserted relative to a drawer unit. The drawer unit includes a photosensitive drum. In a case where the developing cartridge is inserted relative to the drawer unit, the photosensitive drum and developing cartridge face each other. Then, the drawer unit attached to the developing cartridge is accommodated inside the image forming apparatus.
Another developing cartridge known in the prior art is inserted relative to a drum unit. The drum unit includes a photosensitive drum. In a case where the developing cartridge is inserted relative to the drum unit, the photosensitive drum and developing cartridge face each other. Then, the drum unit attached to the developing cartridge is attached to the image forming apparatus.